Epigenetics is a new science that demonstrates a link between the lifestyle choices you make for your dog or cat (and yourself!), and how her genes express themselves.
Do you ever wonder why puppies or kittens from the same litter end up with different health issues and lifespans? Why would similar gene combinations produce such varied responses in individual animals? A gene is made of DNA and does not change. However, scientists have recently shown that we (and our animals) can actually change how our
genes express themselves. The way a gene causes the body to respond can be altered by lifestyle choices. This new field of study is called epigenetics. This article will briefly cover the science of epigenetics, and focus on specific (though still to be proven as epigenetic) ways you can improve your dog or cat’s health and longevity.
A brief explanation of epigenetics
The term “epigenetics” (the prefix “epi” is a Greek term for “above”, “outside of ” or “around”) was coined in 1942, before DNA was even discovered. It is defined as the study of external or environmental factors that turn genes on and off, and affect how cells interpret and express genetic code.
The epigenome is made up of chemical compounds and proteins that can attach to DNA and direct actions such as turning genes on or off, and controlling the production of proteins in particular cells. This process can be either beneficial or detrimental. DNA methylation adds a methyl group to part of the DNA molecule, called a mark, which prevents certain genes from being expressed. Demethylation does the opposite. These processes do not change the sequence of the DNA; rather, they change the way cells use the DNA’s instructions. The marks are sometimes passed on from cell to cell as the cells divide. They can also be passed down from one generation to the next.
Two aspects of epigenetics have been studied
1. One area of study involves how genetic expression in the embryo is guided to form heart cells, muscles, nerves, skin cells, etc. Each has the same DNA, but the instructions they get makes them unique. For example, skin cells have the gene for collagen turned on, while it’s turned off for liver cells.
In utero influences come from the mother and father. Studies have shown that the mother’s nutritional status, and even her emotional state, influence the developing fetus. This could explain many of the challenges faced by puppy mill animals. These inheritable epigenetic changes in gene expression are responsive to environmental influences. Genetic mutations of DNA sequences, on the other hand, are not affected.
2. The other area of study looks at how factors after birth (especially when cells are still rapidly dividing in the kitten or puppy), such as environment, hormones, stress and nutrition, can affect gene expression. These factors can be beneficial or damaging, and are individualized.
Diet and exercise have been shown to turn genes on and off. For example, researchers have identified compounds found in broccoli that can switch on a specific gene that helps the body detoxify harmful chemicals; however, 20% of people do not have that gene. The American Kennel Club’s Canine Health Foundation is funding several studies on epigenetics. One, published in a journal called Aging, “demonstrates that DNA methylation and epigenetic aging in dogs resembles that in humans. Epigenetic modifications, such as DNA methylation, can be reversible.
DIET AND EXERCISE HAVE BEEN
SHOWN TO TURN GENES ON AND OFF.
Therefore, researchers may find methods to alter aging and the development of diseases such as cancer in humans and dogs.” Two more studies have begun to examine B–cell lymphoma in golden retrievers.
Using epigenetic theory to build health
Epigenetic effects are everywhere. They can include your dog or cat’s location, how he exercises, or the chemicals he’s exposed to. Vaccinations, de-wormers, medications, pesticides, heavy metals and other toxins can all change your animal’s epigenome and contribute to unwanted epigenetic changes.
For example, a dog or cat may be born with genetics that predispose her to allergic reactions to many different foods and chemicals; however, if she is never exposed to these specific substances, she will never show symptoms.
The time to maximize epigenetic input is when the animal is young. Wean her to a fresh food diet. Pay close attention to the environment, encourage exercise, and minimize chemicals. Consider waiting as long as possible to give vaccines, and/or explore natural immunity.
Even in older animals, foods can improve the epigenome through methylation, which can help prevent inflammation. “An important aim of nutrigenomics involves identifying the markers of early phases of diet-related diseases, so that nutritional intervention can return the patient to a healthy state,” says veterinarian Dr. Jean Dodds. “Another aim is to demonstrate the effects of biologically active food components on health, leading to the design of functional foods that will keep individuals healthy according to their own specific needs.”
Epigenetics is a new and developing science. We still have much to learn about how it can be applied to canine and feline health, as well as our own. But what we know so far indicates we have more control over our genetic expression — and that of our dogs and cats — than we think we do.
EPIGENETICS AND EXERCISE
Exercise also plays a role when it comes to epigenetic theory, even before birth. A human study, which can likely also be applied to dogs and cats, showed that exercise during gestation actually protects the growing embryo from acquiring the harmful effects of parental obesity by offsetting abnormal DNA methylation transmission to the
Another study found that “exercising can turn off the genes responsible for some of the negative brain effects of alcohol.” Although our dogs and cats don’t drink alcohol, they are exposed to a lot of other toxins, so this study can help us realize how important exercise is for our animal companions.